SEATTLE — Microsoft co-founder and Seahawks owner Paul Allen has died from complications associated with non-Hodgkin's lymphoma. He was 65.

"Paul’s family and friends were blessed to experience his wit, warmth, his generosity and deep concern," Jody Allen, Paul Allen's sister, said in a statement. "For all the demands on his schedule, there was always time for family and friends. At this time of loss and grief for us – and so many others – we are profoundly grateful for the care and concern he demonstrated every day."

Allen announced two weeks ago his non-Hodgkins Lymphoma was back nine years after he was first treated for the disease. Allen wrote in a blog post that he had begun undergoing treatment and planned to fight it “aggressively.”

Non-Hodgkin’s lymphoma is a cancer that starts in the white blood cells.

WATCH: CEO of Allen's investment company Vulcan reacts to Allen's death

Allen and Microsoft co-founder Bill Gates met while attending Lakeside School, a private school in north Seattle. The two friends would later drop out of college to pursue the future they envisioned: A world with a computer in every home.

Gates so strongly believed it that he left Harvard University in his junior year to devote himself full-time to his and Allen's startup, originally called Micro-Soft. Allen spent two years at Washington State University before dropping out as well.

They founded the company in Albuquerque, New Mexico, and their first product was a computer language for the Altair hobby-kit personal computer, giving hobbyists a basic way to program and operate the machine.

After Gates and Allen found some success selling their programming language, MS-Basic, the Seattle natives moved their business in 1979 to Bellevue, Washington, not far from its eventual home in Redmond.

"Personal computing would not have existed without him," Gates said in a statement.

Microsoft's big break came in 1980, when IBM Corp. decided to move into personal computers and asked Microsoft to provide the operating system.

RELATED: How Allen, Gates brought a computer into every home

Gates and company didn't invent the operating system. To meet IBM's needs, they spent $50,000 to buy one known as QDOS from another programmer, Tim Paterson. Eventually the product, refined by Microsoft — and renamed DOS, for Disk Operating System — became the core of IBM PCs and their clones, catapulting Microsoft into its dominant position in the PC industry.

The first versions of two classic Microsoft products, Microsoft Word and the Windows operating system, were released in 1983. By 1991, Microsoft's operating systems were used by 93 percent of the world's personal computers.

WATCH: Tech community remembers Allen as a big thinker

The Windows operating system is now used on most of the world's desktop computers, and Word is the cornerstone of the company's prevalent Office products.

Microsoft was thrust onto the throne of technology and soon Gates and Allen became billionaires.

"Paul Allen's contributions to our company, our industry and to our community are indispensable," Microsoft CEO Satya Nadella said in a statement. "As co-founder of Microsoft, in his own quiet and persistent way, he created magical products, experiences, and institutions, and in doing so, he changed the world."

Gates said in a statement he was "heartbroken" by the death of Allen, who he called his "true partner and dear friend."

"Paul loved life and those around him, and we all cherished him in return," Gates said. "He deserved much more time, but his contributions to the world of technology and philanthropy will live on for generations to come."

Allen served as Microsoft's executive vice president of research and new product development until 1983, when he resigned after being diagnosed with Hodgkin's lymphoma.

"To be 30 years old and have that kind of shock — to face your mortality — really makes you feel like you should do some of the things that you haven't done yet," Allen said in a 2000 book, "Inside Out: Microsoft in Our Own Words," published to celebrate 25 years of Microsoft.

Outside of technology, Allen also had a hold on sports in the Pacific Northwest, taking ownership of the Seattle Seahawks in 1997 and saving the team from relocation.

WATCH: 2014 interview with Allen after Seahawks Superbowl win

Seahawks head coach Pete Carroll tweeted Monday that he was deeply saddened by Allen's death, and that his legacy would live on.

"His gracious leadership and tremendous inspiration will never be forgotten," Carroll said. "The world is a better place because of Paul’s passion, commitment, and selflessness."

In 1988 at the age of 35, he bought the Portland Trail Blazers professional basketball team. He told The Associated Press that "for a true fan of the game, this is a dream come true."

He also held a minority ownership in the Seattle Sounders FC, which he acquired in 2009 when MLS expanded to Seattle.

RELATED: Timeline of Allen's impact on Pacific Northwest

Additionally known for his work in the community, Allen’s philanthropic contributions exceed $2 billion, according to his website. In March 2017, Allen committed $30 million to fighting homelessness in Seattle by creating new housing. He also pledged $100 million in 2014 to fight the Ebola crisis.

He was awarded the Carnegie Medal of Philanthropy in 2015 for his philanthropic efforts.

Through his investment company Vulcan, Allen continued exhibiting his entrepreneurial spirit through scientific and space explorations, real estate and capital investments, conservation, and global health.

“Paul had a tremendously huge vision on how to improve the world, and a big part of our forward plans are to help realize that vision and to continue what he wanted to get done,” Vulcan CEO Bill Hilf said Monday.

WATCH: Allen gives $300 million to brain science in 2014

The Allen Institute, which was founded in 2003, has three branches that expand scientific research in brain science, cell science, and bioscience.

"Paul’s vision and insight have been an inspiration to me and to many others both here at the Institute that bears his name, and in the myriad of other areas that made up the fantastic universe of his interests," Allan Jones, president and CEO of the Allen Institute, said in a statement. "He will be sorely missed."

RELATED: 'Our world has lost a force for good': Community reacts to Allen death

His influence is firmly imprinted on the cultural landscape of Seattle and the Pacific Northwest, from the bright metallic Museum of Pop Culture designed by architect Frank Gehry to the computer science center at the University of Washington that bears his name.

Radio station KEXP remembered Allen as a lover of music who made several large gifts to the station, including a $3.6 million gift in 2001, which helped the station become independent of the University of Washington, and a $500,000 gift in 2016 that helped the station complete a fundraising campaign for a new facility at Seattle Center.

"He had a wide and deep array of interests, but one unceasing interest through that was music," said KEXP Executive Director Tom Mara.

WATCH: Allen’s impact on arts, culture in Seattle

Washington Governor Jay Inslee said in a statement that Allen "personified Washington state" through his technological contributions, philanthropic work, and scientific endeavors.

"Paul was a person who pushed so many intellectual envelopes and expanded human knowledge, and his legacy will live beyond bricks and mortar," Inslee said.

Amazon CEO Jeff Bezos also said he was sad to hear of Allen's death.

"His passion for invention and pushing forward inspired so many," Bezos tweeted. "He was relentless to the end."

The Associated Press contributed.